Method of making grape sugar



Oct. 23 1923.

w. B. NEWKIRK METHOD oF MAKING GRAPE SUGAR rneaaaoeeza, 1923.

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y To all'w/aomz'tmay concern.'

Be it known that I, WILLIAM B. Newman, a citizen of the United States, residing a't .Edgewater, in the county of Belgen and 6 VState of New Jersey, have invente certain 'new and useful Improvements in Methods ,v of Making Grape Sugar, of which the following is a specification. q i My invention is concerned with the manu- 10 facture of grape sugar (dextrose) from starch or starch bearing materials and relates, more particularly, to the crystallization of the dextrose in the converted liquor and the separation of the sugar from the l5 mother liquor in a c 'stalline state and substantially free from impurities.

` 'The object of the invention is to make possible the production, on a commercial scale and b methods' which are economicall feasible o a crystalline dextrose which wi l be to Vall intents and purposes ure (99 to 100% dextrose calculated on the asis of dry substances). v

It has lon been customary to make a solid sugar rom starch by converting' the starch, concentrating the converted liquor, pouring this liquor into molds, or casting on a'loor, and allowing the same to stand until hard and then curing the blocks of sugar by heat and pressing or centrifuging the material to extract the mother liquor commonly called hydrol in the trad One of the disadvantages of this method is that the sugar-contains quite a large percentage of unconverted dextrines, protein substances and other impurities, the purity being in no case, so far as I am aware, greater than 95%. Moreover, the process consumes a long period of time, requires a large amount of 1abor, much l'loor space, and involves a large loss of dextrosewhich is pressed out with the mother li uor.

I have foun thatby making quite a radivcal departure from the method usually em-A ployed in the manufacture of grape sugar, a sugar of very close to absolute purity can be produced by a process `which is relatively l simple and is economically practical.l Dextrose or grape sugar of high purity has been made heretofore, but never, so far as I am aware, on a commercial scale by methods which can be regarded as feasible from an economic point of view.' Y

The present process involves, 'in the first ter.

the repeated treatment of the converted li uor. That is to say, after crystallization as been induced in the liquor received from the converters and the sugar crystals. separated therefrom the mother liquor or hydrol is 'retreated once, or it may be twice, to produce a second, and,if desired,

a third yield of sugar crystals. It has been customary to treat sucrose in a 4manner somewhat analogous to this, the readiness of the molasses to crystallize naturally suggesting this expedient; but as there seems to be no natural tendency of the hydrol of grape sugar to crystallize, the re-treatment of the converted liquorhas not heretofore suggested itself as a workable possibility to manufacturers of this product. The retreatment, obviously, is not essentialy but 'it is, nevertheless, Ibelieve, quite necessary,

for reasons ot' economy, inV order that the v yield of the sugar from a given batch ofthe '75 converted liquor be sufficient 'in quantity to warrant the undertaking. .Theattempt to obtain any veryconsiderable' percentage of the dextrose by one crystallizing operation is not feasible because of the length of time required, and also because of the tendency of the liquor to thicken if allowed to stand4 toolong, thereby preventin lthe separation as between crystals and lmotgl'ier liquor.

In the second place, the conditions as to temperature and density of the liqor un' der which crystallization isinduced must be so regulated as to produce crystals of relatively uniform character, otherwise the comp'lete extraction of the hydrol is not possible.

`rape sugar may consist of either h drate or anhydrous crystals ormixtures ofy both, accrdingto the conditions present during the crystallizing operation. The crystals may be of relatively uniform size or of dif- 95 fering sizes, dependent also upon conditions capable, I have found, of regulation. In order to make it possible .to completely extract the hydrol by centrifuging, for example, which is apparently the only feasible method, the crystals must beof oneV class or the other, hydrate or anhydrous, and of approximately uniformY size, the larger the bet- Any considerable quantity of small crystals will result in the formation of aV m5 dense film in the centrifuval machine which revents the liquid from lbeing' thrown out. ile it is possible by'my process to make place,

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either aV hydrate sugar or an anhydrous sugar, de ndent u n the .temperature `maintain during t e crystalhzmg operation, the process should be regulated so as to produce either one type of crystals or the other, not a mixture of both. t should be further regulated so as to insure the formation of crystals of a vrelatively uniform large slze. Failure of previous experimenters to realize the importance of these considerations accounts for the practical unworkabilityof many of the pr described in the literature for manufacturin high purity grape sugar. By accident w en conditions (unknown in large part to the experimenters) were just ri ht a satisfactory product might be produc But there was no certainty that another batch treated in apparently the same waywould rnot prove a failure. Obviousl manufacture on a commercial scale undler these conditions was impossible. Other processes theoretically possible have roved too expensive for commercial utility. ence a literature disclosing apparentl repeated successful solutions of a pro lem which, asa matter of fact, has not, prior to the present invention, received any really practical solution.

My invention contemplates, as stated, either two successive treatments of the converted liquor or three such treatments. The process involving but two treatments of the converted liquor will, be termed the twoboiling process. The process involvin three treatments of the converted liquor t at is, two successive treatments of the hydrol, will he termed the three-boiling process.

The accompanying drawing is a diagram illustrating the three-boiling process. It also illustrates incidentally the preferred two-boiling process as well as a certain modification thereof.

Referring to this diagram, the syrup or converted l1 ucr, produced, for example, by the acid hy rolysis of starch in which the conversion is carried as far as possible, say to dextrose (based on dry substances), is first purified, preferably, by being passed through the bone char filter A and is then run, through pipe l, to storage tank B. This liquor will ordlnarily have a density of approximately 30 Baum. It is conducted through pipe 2 to a vacuum pan C where it is concentrated to a densit of from 38 to 45 Baume. The preferab e density is 40 Baum and, as a matter of fact, the density should be as high as possible so as to shorten the time without running the risk of having the liquor so viscous as to be unworkable in the later stages Vof the process and without running the risk of havin too high a de ee of supersaturation whic may cause f se grain. The tendency of the liquor to become viscous when concentrated is due to .the presence of the dextrine and other lmpurities. Therefore the extent to which concentration can be carried will depend upon the character of the sugar liquors, their urity, the

n carried, and the nature of the unconverted or partially converted products therein. From the vacuum pan the concentrated liquor is run through pipe 3 into a crystallizing vessel D which consists preferably of a water 'jacketed vessel having an agitator d therein. The purpose of the agitator is to kee the' magma in slow motion during crysta ization so as to constantly bring new mother liquor to the growing crystals. Otherwise the crystals as they formwill settle to the bottom and the supernatant mother liquor will be likely to throw out false grain. The liquorcoming from the vacuum pan will be relatively hot. It may have a temperature approximating 140 Fahrenheit. If hydrate sugar is to be manufactured the liquor in the crystallizer should be cooled down to from to 105 Fahrenheit and should be held at this temperature until the crystallization is completed, an operation requiring ordinarily about thirty hours, but sometimes for a longer period up to sixty hours, depending upon the character of the sugar liquor treated. If the liquor introduced into the crystallizer has a density of 40 Baume (this and other densities being based upon a temperature of Fahrenheit as is customary 1n the art), the best temperature during crystallization is 100 Fahrenheit. There is a direct relationship between the temperature Vof crystallization and the density of the liquor. If the liquor is heavier than 40 Baumthe temperature should be highe If the density of the liquor is less than 40 Baum the temperature must be lower. The upper limit of density, however, is fixed by the character of the liquor as above set forth, and it is not practlcal to use a liquor substantiallylighter than 38 Baume because with the lower temperature the crystallizing operation is much prolonged and this is undesirable for economic reasons, and, second, because of the tendency of the dextrose to form relatively small crystals at the lower temperatures. From the point of view of economy it should be the aim to crystallize at the highest practical density and temperature. All my experience goes to show that in order to obtain satisfactory results crystallization must take place, for hydrate sugar, within the ranges of densities and temperatures given, namely, 38 to 45 Baume and 95 to 105 Fahrenheit. The cooling of the liquor is accomplished preferably by circulatlng cold water through the water jacket of the crystallizer. The reason for artificial cooling is that at the high temperatures anhydrous dextrose might be extent to which conversion has until the crystallization is complete. the

formed, so that it is desirable to cool the sclu ion down to the temperature favorable for ydrated angler as quickly as possible. When the liquor as been reduced to the desired temperature it is important to maintain it at approximately that temperatui' a su liquor is merely allowed to stanrunpetil lacols it will become solider semi-solid as it crystallizes and the crystals, moreover, will be a mixture of hydrate and anhydrous crystals ofvarious sizes. Under such conditions the complete removal of the hydrol from the sugar is impossible.

After crystallization has taken place the material is introduced into a centrifugal machine orhydro extractor E through pipe 4 and the mother liquor or hydrol extracted by centrifugal' action. The sugar may be washed by water from pipe 5 and will be found to contain from 99% to 100% of dextrose, calculated on dry substances and not counting the water of crystallization.

The hydrol from the hydro extractor E (first hydrol) is then, preferably, run

through pipe 6 to the filter F and from there through pipe 7 to storage tank G from which itis drawn through pipe 8 intov a second vacuum pan H. The first hydrol contains, of course, a smaller dextrose content than the original converted liquor. It may contain, for example, 82% of dextrose. Its density has been decreased by extraction of a part of its sugar. The purpose of reboiling the hydrol is to increase its density. Preferably it is concentrated to' a density of from 38 to 42 Baume'. Here again the concentration should be carried, for economic reasons, as high as possible but inasmuch as the hydrol will contain a lar er percentage of dextrine and other impuritles than the original converted liquor and has a higher viscosity, it is not desirable to concentrate the liquor in vacuum pan H to as high a point as the original converted liquor concentrated in vacuum pan C. The concentrated liquor from vacuum pan H is run through pipe 9 to a second crystallizer J, preferably identical with crystallizer D. The liquor is cooled to from approximately 90 to 100 Fahrenheit, de-

pending upon density, and is held at this temperature until crystallization isV complete. The material is then run through pipe 10 to a second hydro extractor K which expels the mother liquor leaving the crystals in the basket. This sugar may be washed with water from pipe 11. I have .found it possible, by the exercise of some care, to produce a second sugar, that is, sugar taken from hydro extractor K, which will Je substantially as pure as sugar from the hydro extractor E. If, howeverthe second sugar is not of the required purity, which may happen in case thel percentage of dextrose in the hydrol is low, or if the' nonsugars do not wash out readily, 'the sugar from hydro extractor K maf7 be introduced by conveyor 12 into the me ter L to which is preferably run, through pipe 13, the wash syrup from hydro extractor E (first wash syrup) and through pipe 14, the wash syrup from hydro extractor K (second wash syrup). v The melted sugar is conducted t rough pipe 15 to filter A where it is mixed with the next batch of converted liquor.

In the two-boiling process above described, the hydrol from hydro extractor K (second hydrol) receives no further treatment. t is a marketable commodity of some but small value.

The process as above outlined may be modified in the following respect. Instead of filtering and concentrating the first hydrol this liquor may be conducted directly, through pipe 16, indicated by the dotted line on t e diagram, to crystallizer J. The liquor being relatively light, crystallization ta es place slowly which is a disadvantage. The modified arrangement, however, has the compensatin advantage of eliminating the-expense of t e filtering and re-boiling steps.

For the three-boiling process the hydrol extracted by hydro extractor K (second hydrol) is conducted through pipe 17 to the filter M and is then run through pipe 18 to the stora e tank N and from the storage tank throug pipe 19 to the third vacuum pan O. The liquor ishere concentrated as highly as its increased viscosity and diminished purity due to the increased percentage of dextrine, etc. will permit, ordinarily to a density` varying from 36 Baume to 40 Baume. It is then run through pipiI 20 to a third crystallizer P where its temperature is reduced to from 90 to 100 Fahrenheit and held at that point until crystallization is complete. The material is then introduced through pipe 21 into a hydro extractor Q where the hydrol is drawn oil' and is'carried out of the process through pipe 22 (third hydrol). The sugar in ythe hydro extractor is washed byy water introduced through pipe 23 and this sugar (third sugar) is carried by conveyor 24 to a melter R into which is introduced through pipe 25 the wash syrup (third wash syrup) from hydro extractor Q. The melted sugar passes through pipe 26 into the filter F where it mixes with the first hydrol. It is sometimes possible to obtain a thirdsugar of sufficiently high purity for 'the market. But ordinarily it requires retreatment as described.

The stallization of the dextrose is facilitatdldybyseeding which may be accomlished by leaving a small amount-of su ar 1n the crystallizer as each batch is withllO drawn therefrom. In fact the seeding of the liquor with hyldrate or anhydrous crystals, according to t e type of sugar to be manufactured, such crystals being conveniently taken from the batch just made previously, has an important hearing on the matten of obtaining uniformity of crystallization throughout the magma,l It has been pointed out that by proper control of the temperature during crystallization one type of crystals or the other, that is, hydrate or anhydrous crystals can be produced. By inducing crystallization through seeding instead of allowing the crystals to form sponta neously, these crystals will all be substantially uniform in size. With the crystals of the same type and of uniform size pu 'ng 1s made practical. It is not practicaw en the crystals are of diverse and different sizes. The process of manu acturin anh drous sugar, as herein disclosed, is .t e su ject matter of a. copendin appllcatlon, filed b me on the 28th day o May, 1923, Serial Nil). 641,886.

The connections between the various elements of the apparatus have been referred to as ipes. It will be understood that any suitab c conduit or conveyor might be used for moving the material from place to place. The invention is not concerned with the particular form of a paratus illustrated diagrammatically inV tlie drawing. It would be possible, for example, to crystalllze the concentrated liquor in the vacuum pan but as a matter of practice it is more convenient to employ a separate crystallizing vessel.

In order to roduce an anhydrous sugar the converted llquor, after having been concentrated, as above described, in connection with the production of hydrate sugar and introduced into the crystallizer D, is cooled down to a temperature of from 110 to 120 Fahrenheit, depending upon its density, the preferable density being 41 Baume and the preferable temperature 115 Fahrenheit. The material is held at this temperature until crystallization takes place. The first sugar from this process will be, as stated, anhydrous sugar, but if the hydrol is retreated the second and third sugars will be hydrate sugars. I do not claim herein, specifically,the manu facture of anhydrous sugar. The process herein disclosed is applicable, in a generic sense, to the production of both kinds of sugar and is so claimed. The specilic claims hereof are, however, limited to the production of hydrated Asu r.

It is realized that even witlnthe fullest disclosure of the invention perfectly satisfactory results are obtainable only by the exercise of some discretion on the part of the o rator so far as concerns the densities of tli liquor in which crystallization is induced and the temperatures at which crystallization should take place. The character of the converted liquor will diier in dierent plants and even when much care is exercised with diierent batches in the same establishililient. Tlile alilln should l tg conentrate th? 'uol-asi aspossi e uttedree' o wdrkable cnclentration will depen upon the character of the particular batch. The temperature of the concentrated liquor should be reduced as quickly as possible at least in the manufacture of the hydrated product, to the temperature at which crys tallization is designed to he brought about and the batch maintained substantially at that temperature during the period of crystallization. While it is not possible to state to a degree the exact temperatures to be employed for hydrate and anhydrous sugars respectively, since temperature will depend upon density and density upon the character o the converted liquor, the density and temperature should be regulated within the limits above indicated so as to produce either hydrate crystals or anhydrous crystals and not a mixture of both. Most attempts to make a high purity su ar have failed because the importance o this was not realized.

It will be apparent from the foregoing considerations that while I have described my invention in what I consider its most desirable form, I realize fully thatl the preferred method above outlined may be modiiied without departure from the principles.

of the invention and will doubtless have to be modified accordin r to varying characteristics of the converte liquor treated. I wish it to be understood, therefore, that the invention is not limited to the specific details of the process as described, except so far as such details are expressl made limitations in the appended clalms. ile I have stated the ranges of temperature and density which I consi er best, it may be possible by exercise of unusual care to work above or below said temperatures or to use higher or lower densities with the risk, however, of false grain and mixed grains and other diliiculties which have been suggested.

I claim:

, 1. The process of obtaining grape sugar in a crystalline state from a dextrose solution produced by conversion of starch which comprises concentrating the solution to super-saturation by heating in vacuo, cooling the solution to and holding the same at a crystallizing temperature. separating the mother liquor from the dextrose crystals. subjecting the mother liquor to a crystallizing temperature at a corresponding density substantially as specified for a second yield of crystals, and thereafter making a separation between the mother liquor and the crystals last formed therein.

2. The process of claim 1 in which the mother liquor obtained from the first seplli) aratiucr operation is concentrated by heating in vacuo and cooled down to the crystallizmgr temperature for production of the second yield of crystals.

3. The process of claim 1 involving additionallv concentrating the mother liquor derived from the second separating operation and thereafter cooling said motheh uor to and maintaining the saine at a crysta lizin temperature for production of a tliird yield of crystals. l

4. The process of claim 3 involving additionally melting the third yield of sugar and adding it to a batch of converted liquor to be subsequently treated in accordance with the claimed process.

5. The process of claim 3 involving additionally melting the third yield of sugar and mixing it with the mother liquor derived from the first separation, in the treatment according to the claimed process of a subsev quent batch of the converted solution.

6. The process of claim 1, in which the converted solution is concentrated to a density 'of from 38 to 45 Baum and its temperature maintained duri crystallization at between 959 and 105 Fa ren eit.

7. The process of claim 1, in which theconverted solution is concentrated to a density of from 38 to 45'Baum, and its temperature maintained during crystallization at bet/Ween 95 and 105' Fahrenheit for, approximately, from 30 to 60 hours.

8. The process of claim 1, in which crystallization is inducedl by the introduction into the magma of previously formed dextrose crystals of the same type as those intended to be grown.

9. The process of manufacturing grape sugar in a crystalline state from a dextrose solution produced by conversion of starch which comprises concentrating the solution to a density of from 38 to 45 Baume, and obtaining a plurality of yields of sugar from the solution by holding the same at a temperature of from to 105 Fahrenheit and b intermittently eentrifuging the liquor uring the crystallizing operation.

10. The process of obtaining two yields of pure grape sugar (99% to 100% dextrose) from a dextrose solution produced by conversion of starch. which consists in supersaturating said solution by heating in vacuo, cooling the solution and holding it at a crystallizing temperature, centrifuging the so tion to separate the crystals from the mother liquor subjecting the mother liquor to a crysta izirg temperature and at a correspondin ensity for a second yield of crystals, an centrifu ing the same to separate the second yield romthe liquor.

11. The rocess of claim 10, in which the converted iquor is concentrated to a density of between 88 and 45 Baum and the crystallization tenFiperature maintained at from 90 to 105 ahrenheit.

12. The process of claim 10, involving additionally the concentration, by heating in vacuo, of the mother liquor derived from the first centrifuging operation,v

13. The' proce of obtaining a hydrate crystalline ape sugar from a dextrose solution pro uced by conversion of starch which comprises concentrating the converted solution to a density of .from 38 to 45 Baume, seeding with hydrate dextrose crystals and cooling and holding the solution at a temperature of from to 105 Fahrenheit, and separati the mother liquor vfrom the dextrose cry S.

14. The process of claim 13, in which the converted solution is artificially and quickly cooled to the temperature at which crystallization takes place.

15. The process of obtaining grape sugar in a crystalline state from a dextrose solution produced by the conversion of starch which comprises concentrating the solution to a density and cooling the same to and holding it at a temperature, in the presence of previously formed crystals of a single type, to induce formation 'of crystals in the solution which are substantially all of a said type and of substantially uniform size, and keeping the solution in slow motion during the crystallizing operation.

16. The process of obtaining a. hydrate crystalline lution pro uced by conversion of starch, which comprises heating the converted solution in vacuo to concentrate the 'same to -a density of from 38 to 45 Baume, seeding with hydrate dextrose crystals and quickly coolingl the solution to a tem rature of from 95 to 105 Fahrenheit, ll'idlding the same at that temperature for approximately from 30 to 60 hours, and centrifuging the solution to separate the mother liquor from the dextrose crystals. y

17. The process of `obtainin grape sugar in a crystalline state from a extrose solution produced by the conversion of starch which comprises concentrating the solution to super saturation by heatin .11i vacuo, cooling the solution to and ho ding the Vsame at a crystallizing temperature, centriuging the magma-to separate the mother liquor (first hydrol) from the dextrose crystals (first sugar), concentrating the first hydrol to su ersaturation b heating in vacuo, cooling t e concentrate hydrol to and holdin the same at a crystallizlng temperature, .an centrifu ing the ma a to separate the mother liquor second ydrol) from the dextrose c stals second sugar). 4

r 18. e process of clalm 17 in which the converted liquor is concentrated to a density of between 38 Baume and45 Baume and ape `sugar from a dextrose so lilV y crystalline grape su cooled, foi-'c stallization, to a tem rature between 95 ahrenheit and 105 ahrenheit, and thelrst .hydrol is concentrated to' second sugar Amelted and the wash water from the first sugar, together with the melted second sugar, introduced into a fresh batch of converted liquor for treatmentas above set forth.

20. lThe process as specified in claim 18 comprising additionally concentrating in, vacuo the second hydrol to a dens1ty of fromv 36 Baume to 40"- Baum, and reducing the temperature of the concentrated liquor to and holdin tween 90 ahrenheit and 100 Fahrenheit, and centrifuging the material to separate the mother liquor (third hydrol) from the dextrose c stals (third sugar) 21. Trhe process of obtainin a hydrate r from a extrose solution produced by t e conversion of starch which comprises concentrating the converted solution to a density, and artificiall cooling the same down to a tem rature avorable t the formation of hy rate crystals' and holding the solution at said temperature in the presence of previously formed hydrate dextrose crystals.

The method of obtaining grape sugar having a purity of between 99% and 100% from a convertedstarch liquor which cons ists in concentrating the liquor to a density the same at a temperature be solution to su and coolingthe same to a temperature to bring about growth of crystals of a single type only, maintaining the magma ati-said temperature and in the resence of previously formed crystals of said t while keepin it` in. motion to cause t e formationl o crystalsof substantially uniform size, then centrifuging the magma to eliminate mother liquor.

23. The method of obtaining a hydrate crystalline grape su tion produced by t e conversion of starch which comprises concentrating the converted solution to supersaturation by heatin V,quickly cooling the solution down throug the temperatures favorable to the production of anh drous crystals to a temperature favorab e to the production of hydrate crystals holding same at the latter temperature until crystallization takes place, and afterward separating the mother liquor from the crystals.

24, The method of obtaining a hydrate crystalline grape su r from a dextrose solution rodueed by t e conversion of starch yvhi comprises concentrating theV converted rsaturation by heating, quickly coolingt e solution down through the temperatures favorable to the production of anhydrous crystals tota temperature favorable to the production of hydrate crystals, 'holdingthe same at the la r temperature and in motion in the resence of previously formed hydrate crystarls until crystallization takes place, and afterward separating the mother liquor from the crystals.

WILLIAM B. NEWKIRK.

r from a dextrose solu- B. ewkirk, of

Certificate of Correction.

fb is hereby certified that the State of Incorporation of the assignee in etters P t No. 1,471 347, granted October 23, 1923, upon the applicatlon of William Ed aber, New Jerse v,`for an im rovement 1n Methods of MII-kw ing. Grape Sugarewas erroneously given as ew York, whereas snic State sh, d have been given as New Jersey as shown b the records of assignments in ioe;' and that the said Letters atent shoui be reed with this correction th e that the same may conform to the record of the case in the Patex0ce- Signed and sealed this 27th day of November, A, D., 1923. ,3 [smh-|- KARL EENNING,

Acting Commissioner of Baten/ts. 

